权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Dose and dose rate effectiveness to determine the risk of low dose radiation to human

确定低剂量辐射对人体风险的剂量和剂量率有效性

基本信息

批准号：
07408031
负责人：
NOMURA Taisei
金额：
$ 6.85万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07408031/
关键词：
Low dose and low dose rate radiation Dose rate effectiveness factor Physical risk Genetic risk Leukemia Solid tumor Mortality and malformation Mutation

项目摘要

1.0.5 and 1.7 Gy of ^<60>Co-gamma radiation was given to 6 weeks old C3H/HeJ and C57BL/6J mice 4 times at 7 days interval at different dose rates from 0.0002 to 0.57 Gy/min, and Dose and Dose Rate Effectiveness Factor (DDREF) was calculated for the risk estimation.(1) There were apparent dose rate effects in leukemia induction. DDREF was 20-40. Delayed increase of solid tumors was also observed by the lowere dose rates.(2) There was a slight reduction of solid tumors by lower dose rate in C57BL/6J mice, but nothing in C3H/HeJ mice (DDREF*1.0). However, dose rate effects were detected in the lung, breast, and pituitary tumors (DDREF*2.3).2. Fetal deaths, malformations somatic mutation and tumors were induced in PTHTF mice after in utero doses of X-rays, ^<60>Co-rays, and ^<252>Cf neutron. About 1/3 reduction of these defects was observed by lower dose rate. RBE of ^<252>Cf was 6-9 for mutation and cancer.3. PLDR and dose rate effects were absent or very small in double strand breaks repair deficient SCID cells, white it was obvious in wild type culture cells, indicating that dose rate effects were caused by double strand breaks repair in the most parts.4. Measurement of the expression level of WT 1 gene is carried out for the liquidators with hematological abnormality after Chernobyl catastrophe, because it is extremely sensitive to detect leukemia in human.

用1.0.5和1.7戈伊<60>的γ射线对6周龄的C3 H/HeJ和C57 BL/6 J小鼠进行4次照射，间隔7天，剂量率为0.0002 ~ 0.57戈伊/min，计算剂量率效应因子（DDREF）进行风险评估。(1)白血病诱导存在明显的剂量率效应。DDREF为20-40。低剂量率也观察到实体瘤延迟增加。(2)在C57 BL/6 J小鼠中，较低的剂量率使实体瘤略有减少，但在C3 H/HeJ小鼠中没有减少（DDREF*1.0）。然而，在肺、乳腺和垂体肿瘤中检测到剂量率效应（DDREF*2.3）。在子宫内剂量的X射线、γ-Co射线和γ-Cf中子后，在PTHTF小鼠中诱导胎儿死亡、畸形体细胞突变和肿瘤<60><252>。在较低的剂量率下，这些缺陷减少了约1/3。对<252>突变和癌症的RBE为6-9.双链断裂修复缺陷的SCID细胞中PLDR和剂量率效应均不存在或很小，野生型培养细胞中则有明显的白色，说明剂量率效应大部分是由双链断裂修复引起的. WT 1基因表达水平的测定是针对切尔诺贝利核电站事故后有血液学异常的清理人员进行的，因为它对人类白血病的检测非常敏感。